[Samba] smb2 max credits did not work as expected

[jie wang]

Hi, all,
  I set smb2 max credits = 70 in smb.conf, but I find more than 200
read requests
were sent to server in 3 seconds, and has no response during this
period. Each read request's
read len is 2MB, and they share the same "credit charge: 32".
  I want to restrict the read request number outstanding at the same
time, i.e. client only send read request max to {max credits} before
receive read response. how can I achieve this?  Thanks a lot.